Although diabetes is commonly undiagnosed and many patients have evidence of complications at diagnosis, there is no definitive evidence that early detection improves health outcomes. One of the critical but uncertain factors is the extent to which screening and subsequent treatment reduces cardiovascular risk. Multi-factorial cardiovascular risk reduction in people with prevalent diabetes and microalbuminuria results in a halving of heart disease risk. However, it is not certain whether this result can be generalised to patients without microalbuminuria or those whose disease is screen-detected.